1. Field of the Invention
The present invention relates to a cardiology patient simulator for medical training, which comprises mannequin made of foam material that has a skin layer on its surface. This simulator is utilized for training of diagnosis, for example, auscultation, palpation, inspection, etc..
2. Description of Related Art
This kind of simulator was disclosed in Japanese Non-examined Patent Publication No. 63-38978.
As shown in FIG. 1, electrocardiogram(ECG), carotid-arterial pulse(CAP), or apex cardiogram(ACG) has subtle waveform although they are a normal wave. Further, heartbeat has different waveform depending on each place (aortic, pulmonic, tricuspid, and mitral), and each of them has also subtle waveform.
Said simulator uses a mechanical system, which has a plunger wherein a solenoid is moved by electric signal wave, to generate arterial pulse, venous pulse, or cardiac impulse. However, it was impossible for said simulator to reproduce subtle waveform because the solenoid can move the plunger only between two positions.
FIGS. 1(b)(c) show examples of each waveform when having a disease. Because both waveforms in contracting (b)aortic stenosis and (c)tricuspid regurgitation are extremely subtle, it is impossible to reproduce those waveforms precisely by using the mechanical system. Thus, medical training, which is carried out by comparing disease waveform with normal waveform, did not meet actual condition.
When operating the solenoid or the plunger mechanically, it gives rise to some noise without exception. Aortic sound(A), pulmonic sounds), tricuspid sound(T) and mitral soundM) are similar to each other as shown in FIG. 1, or they can be similar to each other by overlapping with such noise. Therefore, there is high possibility of misdiagnosis when said system generates arterial pulse, venous pulse, or cardiac impulse mechanically in the simulator, and hence the simulator can not achieve its purpose.
Further, a simulator for auscultation training of heart sound is disclosed in Japanese Examined Patent Publication No. 5-27113. This simulator has speakers which reproduce recorded normal and diseased heart sound for training of heart auscultation. However, as shown in FIG. 1, since cardiac disease changes arterial pulse, venous pulse, cardiac impulse and respiration as well as heart sound, it is necessary to diagnose heart sound and all of these pulses totally. Therefore, a simulator for medical training which can generate heart sound and these pulses is expected.
1. Objects of the Invention
An object of the present invention is to provide an improved simulator for medical training which generates arterial pulse, venous pulse, cardiac impulse, respiration, etc. precisely without any vibration sound or noise.
2. Technical Means
The technical means for attaining the above object is to generate physiological phenomenon, for example, pulsation, heartbeat, respiration, etc. in diagnosis positions by utilizing a change of air pressure and to change air pressure by an air supplier controlled by an electric signal supplier.
Generating pulsation, heartbeat, respiration, etc. by utilizing the change of air pressure, it gives rise to no mechanical vibration sound reaching diagnosis positions through air. Therefore, there is no possibility of giving rise to any noise when diagnosing. Further, since air pressure is changed by the air supplier controlled by the electric signal supplier, it is possible to generate normal wave and disease wave precisely by adjusting air pressure subtly.
Air pressure is changed, for example, by the air supplier with an electric-air proportional control valves controlled by the electric signal supplier.
Therefore, the simulator of the present invention enables to reproduce pulsation, heartbeat, respiration, etc. precisely in diagnosis positions without generating any mechanical vibration.
Incidentally, it is preferable to adopt a foam material, which forms the mannequin, whose elasticity is similar to that of human body and whose conductivity of sound is small. For example, a urethane foam or vinyl chloride foam is suitable therefor. Also soft vinyl chlorides or silicone resins are suitable for the skin layer.
In detail, the technical means for diagnosing pulsation is to place a tube, which changes its thickness by inside air pressure, along the back side of the skin layer in a pulsation position, to support the tube from the back side of the mannequin by a supporter made from soft material, and to generate pulsation by supplying said tube with air.
Since the present invention generates pulsation by changing air pressure inside the tube, it enables to reproduce the expansion and contraction of vessel without mechanical vibration. And since the tube is placed along the back side of the skin layer being supported by the supporter, it is possible to exactly diagnose the expansion and contraction of the tube as pulsation of vessel.
Further, since the supporter is made of soft material such as soft rubbers or soft synthetic resins, it is possible to reproduce feeling in a finger that is similar to the human body diagnosis, and to prevent the tube from damage.
It is preferable to use soft rubbers or synthetic resins for the tube, so that the tube could be flexible and strong as the substitution of vessel. For example, a thin silicone rubber tube, which is 4 to 6.5 mm in a diameter and is 0.2 to 0.6 mm in thickness, is suitable therefor. However, it is preferable to choose the material for said tube taking into consideration thickness and hardness of the skin layer, thickness of vessel, strength and weakness of pulsation, etc.
The technical means for diagnosing cardiac impulses is, in detail, to place an air pump expanding and contracting by supplied air, to transmit expansion and contracting of the air pump to the skin layer in a cardiac impulses position by a transmitter, which includes plural transmitting members having different natural frequency from each other.
Since cardiac impulses are generated by changing air pressure supplied to the air pump, it is possible to reproduce cardiac impulses without any mechanical vibration. Since the expansion and contraction of the air pump is transmitted to the skin layer by the transmitter, it is possible to diagnose exactly as cardiac impulses the movement of the transmitter. Since the transmitter includes plural transmitting members having different natural frequency from each other and the expansion and contraction of the air pump is transmitted through said members, it is able to prevent the transmitter resonating. When the transmitter comprises a touching member which touches the skin layer, a stand which is equipped the air pump, and an arm which connects the touching member with the stand, it is preferable that all the stand, the touching member and the arm have different natural frequency from each other in order to prevent resonating almost perfectly.
And an arm, which constitutes said transmitter, connects with the air pump in the direction crossing the expansion and contraction direction of the air pump. Even if the air pump generates any sound, such sound propagates in the expansion and contraction direction of the air pump. Therefore, it is possible to suppress propagation of such sound through the arm.
The technical means for diagnosing respiration is, in detail, to place an air bag, wherein an air permeable and sound insulating sheet is confined, inside of the abdomen or chest of the mannequin, and to generate respiration by supplying air into the air bag.
Since respiration generates by supplying air to the air bag placed inside the abdomen or chest of the mannequin, it is possible to reproduce the expansion or contraction of the abdomen or chest. Further, since the air permeable and sound insulating sheet is confined in the air bag, it is possible to diagnose respiration exactly without any noise when the air bag expands and contracts by the supply of air.
It is preferable to form the air bag by using the air permeable materials such as synthetic resins or rubbers. Sponges, aerated rubbers, synthetic resin foams, non-woven fabrics, etc. are suitable for the air permeable and sound insulating sheet. Although it is preferable to use the materials whose specific gravity is high as such materials can insulate sound well, it is also desirable to consider if such materials are easy to process or to treat. Glass fiber non-woven fabrics are suitable for the sound insulating materials of the present invention as the same can insulate sound well and are easy to process.
Another technical means for examining heart disease, in detail, to place a speaker, connected with a cardiac sound reproducer, behind the chest of the mannequin, to control the cardiac sound reproducer and the air supplier which operates corresponding to arterial pulse, venous pulse, cardiac impulse or respiration by the electric signal supplier, and to synchronize variation of air pressure with sound reproduction.
Since the speaker connected with the recorded cardiac sound reproducer is installed behind the chest of the mannequin, it is possible to listen to cardiac sound only by putting a stethoscope to the chest of the mannequin. And since pulsation, cardiac impulse, or respiration are generated by changing air pressure supplied to the air pump, it is possible to reproduce them without any mechanical vibration. Since variation of air pressure, which generates pulsation, cardiac impulse, or respiration, is synchronized with sound reproduction, it is possible to coincide cardiac sound required for cardiac diagnosis with physiological phenomenon. Thus, the present invention enables more precise training of cardiac diagnosis.
Further, there is another technical means in connection with the air supplier, in detail, to insert an air inhalant pipe into a sealed cylinder from its one side and an air exhaust pipe from another side of the sealed cylinder, and to intervene an air permeable and sound insulating material between the air flow way of both pipes.
Since the air inhalant pipe is inserted from one side of the sealed cylinder and the air exhaust pipe is inserted from another side of said cylinder, the supplied air never flows from the air inhalant pipe to the air exhaust pipe directly without being exhausted once into said cylinder. And since the air permeable and sound insulating material is intervened between the flow ways of both pipes, the air flowing from the air inhalant pipe to the air exhaust pipe passes through said material and hence mixed noises are almost eliminated.
The way to make air pass through the air permeable and sound insulating material is to cover the end of said pipes with caps made from sound insulating material or to form a partition made from sound insulating material inside of said cylinder. Another way is to form the total of the portions, which exist inside of said cylinder, of the air inhalant pipe and the air exhaust pipe, longer than said cylinder and to intervene an air permeable and sound insulating partition between both pipes.
Therefore, the present invention enables more precise diagnosis as air is supplied to the tube, the pipes and the air bag which reproduce arterial pulse, venous pulse, cardiac impulse and respiration without any noise.
Still another technical means is, in connection with an adjusting device, in detail, to equip the mid portion of the air supply pipe with a diverging coupler, and connect a branch pipe to the diverging coupler, and to equip the top end of the branch pipe with an air pressure control valve.
Since the ratio of time of inspiration to expiration is 3 to 2 regarding respiration as physiological phenomenon, it is impossible to maintain said ratio only by adjusting air pressure.
Since the diverging coupler is equipped the mid portion of the air supply pipe to the air bag and the branch pipe is connected with the diverging coupler, it is possible to adjust volume of supply air and volume of exhaust air from the air bag by utilizing the diverging coupler and the branch pipe.
Since the air pressure control valve is equipped the top end of the branch pipe, it is possible to reproduce respiration as physiological phenomenon, as the ratio of period of inspiration to expiration can be 3:2 by adjusting the air pressure control valve and the diverging coupler. Although air friction sound is given rise to when exhaust air is passing through the air pressure control valve, it is possible to auscultate natural respiration since said air friction sound reproduces expiration sound just as it is.